The Severn Bridge crossing is Free

Prices tolls and costs to cross over.  
The Severn Bridge was open by HM the Queen on the 8th September 1966.
The Bridge is a 1594 Metres ( 5240 feet ) long suspension bridge with a deck that is supported by two main cables between two steel towers.
The Severn Bridge is in almost exactly the same location as the old Aust Ferry.
The towers rise approximately 120 metres ( 400 feet ) above the river and are of hollow box construction.

Tarriffs and crossing charges are removed from the Servern Bridge crossing as of the 17th Decemeber 2018. Charges on the M4 and M48 Servern Bridges have been abolished which may save commuters up to £1,400 per year.
There are no Tolls charged for the Westwards ( towards Bristol ) direction Only anymore.
Motor Car, including Motor Car with three wheels Up to 9 Seats FREE
Light or Medium Goods Vehicle, Motor Coach, up to 17 seats or up to 3,500KG FREE
HGV, Motor Coach, vehicles with 18 seats or more from 3,500KG upwards FREE
Trailer - there is no extra charge for trailers or Caravans Free
Disabled Persons vehicles, no charge if a holder of blue disabled badge Free

Disabled Badge Holders Procedure:
When arriving at a manned toll booth, you should hand your Blue Disabled Persons Badge to the Toll Collector. The Toll Collector will then check the validity of the Badge, that the Badge Holder is in the vehicle and will record the Badge details. The Badge Holder will then be asked to sign a form, if they are unable to sign, the driver can sign on their behalf. The Badge will be returned and the barrier raised for you and so you may continue your journey.
Motorcycles and Disabled Badge Holders are exempt from Toll charges. Also there is No extra charge for towing Caravans / Trailers.